Many news sources have been indexed by special projects, historical societies, etc.  For holdings in Perkins/Bostock Library, look in the author-title catalog for the specific name of the newspaper, or the subject catalog under the following types of headings:

CLEVELAND PLAIN DEALER (specific name of the newspaper)
AMERICAN NEWSPAPERS - INDEXES
AMERICAN NEWSPAPERS - NORTH CAROLINA - INDEXES
AMERICAN NEWSPAPERS - CLEVELAND - INDEXES

For additional information about indexes which may be available in other libraries, see:

Newspaper Indexes: A Location and Subject Guide for Researchers
Anita Cheek Milner.  3v., 1977-1982

Call Number: RZ071  M659N

Useful, although incomplete source, for location of a variety of newspaper indexes in the United States.  The major portion of each volume covers newspaper indexes by state and then alphabetically by title.  Included are dates, indexes, coverage and symbol of repository where index is located.  The second part of each book lists the repository libraries by symbol and includes type of service offered and fees.  Besides indexes to newspapers in individual states, Milner's books cover the following special types of newspapers and their indexes: American Foreign Language Newspapers; Church Publications and Denominational Indexing; United States Regions; United States Possessions; and some Foreign Newspapers.